This invention relates to a radar apparatus which is defined for the purpose of this description as apparatus which derives information about its environment by transmitting energy and sensing the direction and timing of energy after reflection or re-transmission from a feature in the environment. Thus, as well as being applicable to conventional radar operating at microwave frequencies, the invention is also applicable to optical and infra-red radar and to sonar apparatus.
A radar is sometimes required to perform a number of specified tasks such as tracking particular targets and/or searching certain specified areas of its environment for targets which present a threat. One way in which this might be done is on a purely priority basis: i.e. those tasks which are considered most urgent (e.g. because they appear first) are started and completed before commencing less urgent tasks. Whilst a system operating on a priority basis can ensure that tasks are performed in the best order, it does not allow the radar to handle an increased workload. This invention is concerned with the problem of allowing an increased workload to be handled.